1. Field of Invention
The present invention pertains to the field of folding tools. More specifically, the present invention is a folding tool, such as a folding knife, having a leaf spring for assisting with opening the tool, and locking the tool in an open position.
2. Description of the Related Art
In the field of tools, folding tools have been known for many years. To this extent, folding knives are also well known. Typically, folding tools are provided with a handle and at least one implement. Each implement is pivotally connected at one end to one end of the handle. The handle is adapted to receive, either internally or externally, each of the implements. The implements include any one or more of a knife blade, a pair of scissors, pliers, eating utensils, screw drivers, and the like.
It is known to provide a means for locking the position of each implement in either or both of a closed and an open position. Further, it is known in the art to provide a means for assisting in the opening and/or closing of the tool. Various devices have been developed to accomplish these and other features of folding tools, and in particular, folding knives. Typical of the art are those devices disclosed in the following U.S. Patents:
Patent No.Inventor(s)Issue Date4,404,748G. WiethoffSep. 20, 19835,060,379V. O. NeelyOct. 29, 19915,440,814D. K. Hall et al.Aug. 15, 19955,511,310G. C. Sessions et al.Apr. 30, 19965,802,722M. Maxey et al.Sep. 8, 19986,145,202K. J. OnionNov. 14, 20006,308,420R. L. MoserOct. 30, 20016,651,344Y. F. ChengNov. 25, 2003D348,599K. SakaiJul. 12, 1994D348,818K. HasegawaJul. 19, 1994D378,982L. C. ThompsonApr. 29, 1997D473,917F. J. Carter IIIApr. 29, 2003D489,956K. RaeMay 18, 2004
Of these patents, the '748 patent issued to Wiethoff discloses a folding knife having a handle with a body forming a pocket into which its blade is normally retracted. The pocket is bounded by two sides of the handle traversed by respective contacts in line with a hole near an end of the blade. One cutout receives a plunger which is rigidly connected with a detent, received within the other cutout by a stem that is integral with either the plunger or the detent and traverses the hole of the blade to serve as its pivotal axle. A spring in the first cutout biases the interconnected plunger and detent into a locking position in which a projection on the detent engages in a notch of the blade to hold it in its retracted or its extended position. The biasing spring may bear directly on a confronting blade surface and co-act with one of its notches to prevent a rapid switch into the extended position.
Neely, in his '379 patent, discloses a folding knife apparatus including a blade having a tang secured to a case or housing. Wedging action between the tang and the case locks the blade open and closed. The tang includes a longitudinally extending slot. The housing includes a pin extending through the longitudinally extending slot. A spring is disposed in the slot and biases the blade against the pin to help lock the blade in place, particularly in the open position. Axial movement of the blade is required to unlock the blade from its open position in order to pivot the blade. A cam relationship exists between a portion of the tang and a portion of the case or housing to urge the blade to the closed position.
The '814 patent issued to D. K. Hall et al., discloses a knife comprising a handle, a blade mounted on the handle, and a pair of side guards mounted on the handle and movable between an open position and a closed position. The pair of side guards encloses at least a portion of the blade when in the closed position. An actuating mechanism is provided for actuating the pair of guards between the open position and the closed position. The actuating mechanism includes a button movable between a forward position and a rear position and operable with the pair of side guards such that when the button is in the forward position, the pair of side guards is moved to the open position and when the button is in the rear position, the pair of side guards is moved to the closed position.
Sessions et al., in their '310 patent, disclose a folding knife including a knife blade and a handle for storing the knife blade. A pivotally biased lock bar is provided for securing the blade in an extended position. The handle is formed of two keyed sections firmly assembled together by cooperation of a lock bar biasing spring with coaxially aligned holes formed in the keyed regions of the handle sections. The lock bar biasing spring is biased outwardly against one end of a rocking type lock mechanism. When the knife blade is fully extended, the biasing spring pivots the lock mechanism about a pin, with the opposing end of the lock mechanism engaging the knife blade tang in order to lock the knife blade in the extended position.
In the '722 patent issued to Maxey et al., a one handed knife is disclosed. The '722 knife includes a handle having upper and lower handle portions. An arcuate recess extends through the upper handle portion. A blade lock release extends from the lower handle portion. A blade is pivotally connected between the upper and lower handle portions. A thumb pin extends from the blade. A tension bar having a first and second ends is slidably connected at its first end to the upper handle portion and its second end extends through the arcuate recess and is connected to the blade. When in a closed position, the blade is partially positioned between the upper and lower handle portions, the thumb pin is positioned on a portion of the blade extending from between the upper and lower handle portions, and the tension bar is in a first tensioned position at a first end of the arcuate recess. When in an open position, the blade extends from the handle, the tension bar is in a second untensioned position at a second end of the arcuate recess and the blade lock release is positioned to prevent the blade from pivoting towards the handle. The blade is caused to pivot from the first closed position into the second open position by application of a force on the thumb pin and away from the handle, the force being of a magnitude able to overcome the tension of the tension bar.
Onion, in the '202 patent, teaches a mechanism in a folding knife that urges the blade to move to an open and alternatively to a closed position. The '202 knife includes a blade member having a tang extending outwardly from the blade, a handle having at least one recessed portion, a bar pivotally connecting the tang and the handle, and a bias element engaging the blade wherein the bias element is housed within the recessed portion of the handle. The biasing element is generally a flexible elongated member which, when the blade is closed, is tensioned. When the blade is moved manually a certain distance, the biasing element serves to complete the movement of the blade, as a result of the release of tension and without the application of further outside force by the user.
Moser, in his '420 patent, teaches a folding knife which includes an elongated handle. The elongated handle includes two spaced-apart sides. An elongated blade defines a working end and a tang at the opposite end within a common plane. A pivot including a pivot axis connects the tang to the handle to permit the blade to pivot selectively into an open position at which the blade extends outwardly from the handle and into a closed position in which the blade is nested into the spacing. The blade is provided with a cam secured eccentric to the pivot axis and spaced from the plane that includes the blade. An operating spring is secured at one end to the handle and has abutting contact with the cam remote from the end in the handle thus selectively resisting the pivoting of the blade to an open position and when in an open position resisting the pivoting of the blade to a closed position.
Cheng, in his '344 patent, discloses foldable knife structure which includes a set block disposed within the handle at the pivot point of the blade. The set block defines a detent notch. A spring is situated at the end of the handle opposite the blade pivot. The distal end of the spring extends to engage the set block. When the blade is extended from or folded into the handle, the spring is biased against the circumferential edge of the set block, causing the set block to produce torsion that rotates the blade out of or into a receiving slot of the handle. The spring assists in extending and retracting the blade from the handle.
The remaining design patents each disclose the ornamental design for a folding knife.